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Part built Allchin 1.5 inch

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derek blake24/12/2019 17:56:15
556 forum posts
140 photos

Thanks John, I will take a look

Clive Brown 124/12/2019 18:01:52
427 forum posts
12 photos

I bought my bevel gears from Reeves', but that was a long time ago and they appear not to list them anymore.

Even so, it's perhaps worth a 'phone call just on the off-chance.

derek blake29/12/2019 16:09:05
556 forum posts
140 photos

No real updates, other than running engine in on air.

i can hear some leak from the clack valve I made and I can see bubbles in the lubricator so there is obviously a leak from cylinder back down the pipe so I’m going to have to adjust the spring or adjust the ball.

however it runs so I’m happy.

i have the video added to YouTube as mentioned for anyone who would like to see the engine running.


Jim Wills 605/02/2020 18:36:09
2 forum posts

I really don’t know if I’ve a right to be here .... I’ve built quite a few model planes, the largest 5 mtrs span motor glider Zenoah 38 powered, now disposed of along with other scale planes due to two heart attacks which have left me with a loss of balance so I can’t look skyward with a trannie in hand lest I topple over. SO I’ve transferred my likings to model live steam trains two years ago, and now the latest.... live steam engines and in particular Showman’s Tractors and their living vans.

Couple of weeks ago I bought a Wilesco Showman’s Tractor and have since replaced its lighting boards lamps with units having 20 LEDs per side..... that not being enough I’ve got a new Maxitrak 3/4” Allchin Showman’s Tractor in the pipeline and due next week, At moment it won’t come with Showman’s Lighting so that is on order separately for fitting later.

I love my motorcycles too and have 4 on the road at the moment...but my current medical condition having a diagnosis of chronic heart failure prevents me from my riding at 82 years young. I’m interested in anything to do with the 3/4”Allchin although I’ve not made it personally, until two years ago I would spend most of my days either in the shed building model planes, or in the garage working on one of my bikes - a Honda Helix but right now my energy levels are regrettably at a low point.


derek blake09/03/2020 22:51:34
556 forum posts
140 photos

Hi Jim

everyone has the right to be on the forum, I’m presently building the Allchin in 1.5inch scale.

derek blake09/03/2020 22:56:13
556 forum posts
140 photos

Hi everyone

So the Allchin has been on the back burner for a while now, no real new progress other than fitting the safety valve and trying to find an easy way to test this to set blow level, any ideas?

I have ran the engine at Christmas on air and it runs very well I think in forward and reverse, I’m just setting up the control rod and lever now.



derek blake10/03/2020 18:46:22
556 forum posts
140 photos

Hi All

if anyone gets time could they please advise the likely causes of knocking when the engine is running.

it started all of a sudden, I can see and feel movement in the crank bearing which is odd as it’s all brand new and started all of a sudden.

the crank moves ever so slightly in the bearing forward and back, I think this knocks and vibrates through the hornplates.

is my only option to make new bearings for a sung fit on the crank, it ran beautifully yesterday but the loud knock started today. Will this movement just come back even if I start all over again, I had plenty if oil on the area.

thanks in advance.


MichaelR10/03/2020 19:27:43
374 forum posts
79 photos

Are your bearings the spilt type ? if so you will be able to take up that very slight play, another area that can cause a knock is the cross head pin bearing, my D&NY engine always had a knock in that area until I fitted a lubricator as photo.

lubricator cup cross head pin.jpg

derek blake10/03/2020 19:38:06
556 forum posts
140 photos

Hi Micheal

unfortunately they are solid bearings, the play is more of a twist that forward and back,

i guess I’m bemused as the engine ran quiet yesterday but just all of a sudden started knocking.



Clive Brown 110/03/2020 19:48:46
427 forum posts
12 photos

Can you tell if it's once per revolution or twice? If it's once, could it be something like the piston rod gland backing off slightly to be hit by the crosshead? That might explain the sudden onset..

derek blake10/03/2020 20:18:51
556 forum posts
140 photos

Hi Clive

Interesting! However when I put my ear to the various areas it does seem to be coming from the crank

derek blake11/03/2020 17:59:28
556 forum posts
140 photos

Good evening

Could someone advise a uk machinist who would be able to machine two eccentric straps.

i hand made these last time but I’d like a better fit, I have two new castings but finding it hard to find anyone on google who machines live steam parts.

funds are not a problem but finding someone is, any advice greatfully received.


derek blake15/03/2020 22:44:57
556 forum posts
140 photos

Hi All

i hope everyone is well, considering the situation at the moment.

i have a quick question regarding the Allchin safety valve, is there any drawing discrepancies on this part of the build.

the valves that drop down into the steam passages, should these be a sliding fit? It’s not very clear on the drawings, I have leaks around these valves even at low pressure.

does anyone have any pictures of the finished valves for reference.

kind regards


derek blake27/03/2020 21:21:45
556 forum posts
140 photos

Hi All

I hope everyone is well, quick question I started to spray paint my engine with acrylic spray paint.

the boiler parts with VHT paint, my question is the boiler cladding would the acrylic spray paint bubble or go soft and waste my time?

thanks in advance

vic francis29/03/2020 07:08:19
40 forum posts
7 photos

Hi Derek, keep up the good work I have used the brushable Maxitrak high temp black for smokebox ect, and even car exhaust/ bulkhead spray paints as well..most people use enamels and colours can be blended with each other then brushed or better sprayed if you have the equipment. For display models cellulose was always used... but it can bubble with heat... but easy to respray... depends on the insulation material? regards vic

derek blake02/04/2020 19:33:41
556 forum posts
140 photos

Hi All

just a quick question, would I be shot by the traction engine supporters if I painted my Allchin tender Black?

is there any Allchin I could model mine on other than the maroon, I’ve had huge trouble with finish with painting the tender let alone chips etc, but satin black stove paint goes on beautiful and is hard wearing.

the wheels, boiler cladding and crankshaft area are maroon.



derek blake09/04/2020 21:53:39
556 forum posts
140 photos


can anyone advise how to get the Allchin safety valve to seal, it’s been made to drawing and the valve seats have been lapped, however it still leaks.

im also unsure how tight the spring should be, I know you would set this up I guess during a steam test but can you test somehow off the engine.



derek blake10/04/2020 13:16:17
556 forum posts
140 photos

Can I ask, the poppets that fit in the safety valve bores, what sort of fit should these have,

the drawing isn’t clear to me, the bore is 7/32, however how wide should the poppets be? Mine are really loose in the bore, should I have made them a sliding fit in the bored?

im getting an air leak straight away any air is added, even as low as 10psi 🤷‍♂️ Is there a better scratch available anywhere showing how they fit into the bores, I’m pulling my hair out trying to get a seal.


derek blake10/04/2020 15:57:12
556 forum posts
140 photos

We I Wonder if anyone could machine the safety valve poppets for me? I will of course pay.

Paul Kemp10/04/2020 18:25:37
485 forum posts
18 photos


Any chance you can post a picture or two of what you have and maybe a shot of the relevant part of the drawing? I am not familiar with the Alchin design. I would assume the "poppets'" have a stem with reliefs machine in to allow the passage of steam and guide the valve onto the seat but maybe not in your case!


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